Combustion apparatus



8- 1942- R. ROBINSON COMBUSTION APPARATUS 4 Sheets-Sheet 1 Filed June 11, 1938 1942- L. R. ROBINSON COMBUSTION APPARATUS Filed June 11, 1938 4 Sheets-Sheet 2 vs 1 F} WWW INVENTOR.

ATTORNEYJ 1942. 1.. R. ROBINSON 2,291,986

COMBUSTION APPARATUS Filed June 11, 1938 4 Sheets-Sheet 3 Z/ i 7Q INVEI VT OR.

Aug. 4, 1942. L. R. ROBINSON COMBUSTION APPARATUS Filed June 11, 1938 4 Sheets-Sheet 4 BY a? P HIVVENTOR. Mfii Patented Aug. 4, 1942 COMBUSTION APPARATUS Lawrence R. Robinson, Zelienople, Pa., assignor,

by mesne assignments, to H. '1. Bradner, Cleveland, Ohio Application June 11, 1938, Serial No. 213,243

4 Claims. (Cl. 110-76) This invention relates to combustion apparatus and more particularly to such apparatus as is used in steam generating boilers and the like where relatively large quantities of fuel are burned, and eflicient heat transfer and combustion are-desired.

An object of the invention is to provide an improved apparatus for use in conjunction with the combustionof fuel which will cause extremely efilcient combustion thereof.

Another object is to provide an improved combustion apparatus which will aid the efficient transfer of heat.

Another object is to provide an improved combustion apparatus which may readily be applied to existing structures.

Another object is to provide an improved combustion apparatus which will possess long li under severe temperature conditions.

Another object is to provide an improved combustion apparatus which will be composed of simple and economically produced parts.

Another object is to provide an improved combustion apparatus which will be rugged in construction.

Another object is to provide an improved combustion apparatus which may be easily repaired or replaced.

Another object is to provide an improved combustion apparatus which will maintain itself in position effectively during motion of the apparatus to which it is applied.

Another object is to provide an improved combustion apparatus which will not become displaced upon contraction or expansion when heated and cooled.

Another object is to provide an improved combustion apparatus which may be caused to deliver correct quantities of air to properly effect combustion.

Another object is to provide an improved combustion apparatus which may be caused to deliver air at correct temperatures to properly effect combustion.

Another object is to provide an improved combustion apparatus which will supply air in varying quantities corersponding to the requirements for etl'ective combustion.

Another object is to provide an improved method of controlling combustion.

Other objects will hereinafter appear.

The invention will be better understood from the description of one practical embodiment thereof, the invention being described as it may be applied within the boiler of a locomotive, this being a situation where it is subjected to unusually severe operating conditions because of a limited space, variable load, vibration, and the like, to which it is subjected. This embodiment is illustrated in the accompanying drawings, in which:

Figure l is an end elevational view of an arch constructed within a locomotive firebox, parts being broken away and shown in section;

Figures 2, 3 and 4 are longitudinal sectional views of the apparatus of Figure 1, taken, respectively, on the lines II-II, III-III, and IV-IV thereof;

Figure 5 is a transverse, partly sectional view, taken on the line V-V of Figures 2, 3, and 4;

Figure 6 is a fragmentary plan view taken on the line VI-VI of Figure 5; and

Figures 7 and 8 are fragmentary perspective views indicating the manner in which the joints between successive blocks are assembled.

This application is a continuation of my copending application, Serial Number 78,339, filed May '1, 1936, as to all subject matter common to the two applications.

A portion 01' a locomotive boiler including the combustion chamber is illustrated, this combustion chamber being defined by grate bars I which support the bed of fuel 2, the forward end of the chamber terminating in a tube sheet 3 to which are secured the ends of fire or flue tubes 4, while the inner and outer throat sheets 5 and 6 of the boiler extend downwardly from below the tube sheet to a point immediately in advance of the grate bars. The top of the combustion chamber is defined by the crown sheet 1 from which are shown depending two siphons 8 each having a neck 8 communicating with the space between the inside and outside throat sheets and two water tubes In roughly paralleling the tubular portions of the siphons.

The front of the combustion chamber is defined by two inclined sheets H and I2 through which is a fire door opening i3 closed by the fire door I, the space between the sheets I l and I2 and also between the throat sheets constituting a part of a water jacket at the sides, ends, and over the top of the combustion chamber to assist the transfer of heat to the water in the boiler. The above parts are all of more or less conventional and well known construction.

It has been the previous practice with parts similar to those above described to burn fuel, such as coal, upon the grate bars, supplying all air necessary for the combustion through the spaces between these grate bars, and permitting the gaseous products of combustion vto pass freely between the syphons and water tubes to the fire or flue tubes which extend through main liquid reservoir portion of the boiler to the smoke box at the front of the locomotive.

By the application of my invention, the passage of the gaseous products of combustion from the bed of fuel to the smoke box is delayed, so that these products have a greater opportunity to transfer their heat to the water within the boiler. Part of the air necessary for supporting the combustion is delivered to these products at spaced points in highly preheated condition, so as to create a type of turbulence producing much more efllcient combustion.

l The apparatus by which I obtain these results consists of a baille wall built of a plurality of sections or blocks of refractory material. This wall in the illustrated embodiment of the invention consists of two more or less distinct portions, a vertical part and an inclined part.

The vertical part is supported upon a base l5, which conveniently may be of cast iron or other metal, and is shown as a substantially rectangular block extending transversely of the forward end of the combustion chamber with intake openings l6 below the grate bars and having passages from these intakes vertically upward to its upper surface. This upper surface is provided with diverging flanges I! and [8 which support the lowermost block of the baille wall.

The base is shown as made in two halves which may be secured together by a tie plate la, which may be fastened by bolts, rivets, welding, or in any other desired manner. Internally the base is reinforced by vertical transverse ribs |5b substantially in alinement with the tubes, in order that the passage of air through the base may be obstructed as little as possible, and these, together with the flanges l1 and I8 and also with the flange l9 (hereinafter mentioned) render the base very rigid and prevent distortion upon changes in temperature.

The base also has a horizontal flange I19 above the end grate bar. A series of holes 20 are provided through this horizontal flange which permit air to pass upwardly through the end of the fuel bed adjacent the base, thus improving the combustion atthis point, and at the same time cooling the base and protecting it from the deteriorating effects of too great heat.

The vertical part of the wall consists of one or more courses of generally rectangular blocks 2| of refractory material, the blocks of each course being spaced to clear the siphons and water tubes.

These blocks are shown as having passages extending upwardly therethrough and the blocks and passages are held in alinement by interfitting bosses and recesses as shown at 22, the lowermost block 24 having a depending tapered base 25 arranged to fit within flanges l1 and IQ of the metal base.

In the installation illustrated there is one block for each space between consecutive combustion chamber side walls, siphons, or water tubes, hence in the illustration, there being two siphons and two water tubes between the side walls, this produces five spaces, and there are five blocks in each course.

The rows of blocks between the water tubes and siphons will be first described. Upon the uppermost course of the vertical wall is a course of elbow-like blocks 26, each of which has an angularly disposed discharge end lying substantially in a plane normal to the axes of the water tubes and siphon necks, and about the discharge opening is formed with a boss 21 having its exterior surface defined by a spherical zone.

This boss is received in a corresponding spherical-zone-shaped recess in the lower surface of a block of the first course constituting the inclined part of the wall. Each block 3! in this part of the wall has on its upper surface a similar spherical zone-shaped boss received in the zoneshaped recess of the next succeeding block.

It will be noted that the cross-sectional area. of the passage 28 through elbow block at the top of the vertical wall is somewhat greater than that 29 in the blocks there below, and that the cross-sectional area of the opening 30 of the blocks constituting the inclined part of the wall is still greater.

This increase in area is so related to the expansion of the air which will pass through these passages that no back pressure or increase in velocity will be imparted to this air as it becomes heated and expands in passing upwardly within the baflie wall.

The flow of air is limited by the size of inlets l6, and, of course, varies with the draft. The relatively large volume and low velocity of the air within the passages in the blocks 3| permit this air to absorb much more heat than would be the case if the passage were all of uniform cross-sectional area and the greater degree of heating this air improves the combustion when it is admitted to the combustion chamber.

The flow of air through inlet l6 can further be regulated, or can be shut off entirely if desired, by means for obstructing the inlet opening, such, for instance, as the damper or valve lia shown in Figure 3. This may be actuated in any desired manner, as by a rod 16b through which an operator may manually adjust the valve l6a or which may be moved by any desired automatic control, such as a temperature responsive device exposed to the air at or near the point where it leaves the interior of the baflle wall. Other automatic controls actuated by the pressure or velocity of the air in or leaving the baflle wall, or by the difference in pressure of velocity of air at the baflie wall and in the main combustion chamber, could, of course, be used to adjust the valve 16a.

The interior 30 of the blocks can be'designed to further reduce the velocity of the air in passing through the baflle wall and to increase the surface of the tile in contact therewith by the addition of projections or fins, in a manner well understood in the art, and, if desired, these fins may be arranged helically to impart a spinning motion and turbulence to the air within the batflewall, thus bringing more air into intimate contact with the sides of the openings 30.

Each row of blocks 3| (constituting the inclined part of the wall) terminates in a second elbow-like block 32 having an upwardly directed outlet shown as tapering slightly to receive the tapered lower end of a tuyere.

The tuyre is made of two sections, a front 34 and a back 35, and at the meeting edges is recessed to provide discharge openings 35 for the passage of air. In addition, the back or rear section is provided with perforations 31 serving as additional air discharge openings.

The blocks forming the inclined part of the wall are supported by the two siphons and by pressure against the side walls of the combustion chamber. They are shown as of four shapes and s zes.

The blocks which span the spaces between successive pipes and siphons each have a concave lower surface 38 and a convex upper surface I! with generally straight sides 40.

These straight sides and the concave lower surface are joined by arcuate or bevelled edges I which may have a curvature approximately equal to that of the siphons or water tubes to be engaged, but described about centers which are slightly closer together than are the center of the siphons or tubes. These edges may be of somewhat lesser curvature than these supports, or even flat, but in any case converge more abruptly than do the surfaces which support them, so that the blocks, upon expanding, may

camthemselves upwardly upon these pipes.

Thus compressive strains in the blocks are avoided, and breakage due to such strains is eliminated.

It is also found that the concave lower faces of these blocks are somewhat flexible and upon expansion tend to flatten slightly, and that such distortion is not disruptive in its effect, but tends merely to change the bearing of the corners 4| upon the tubes without wedging the blocks between the tubes, so that likelihood of compressive forces which were present in blocks having flat or convex lower surfaces is further reduced.

Those blocks Ill between the side walls and the first adjacent tubes are generally trapezoidal in plan section, each having a lower corner ill provided with a parti-cylindricai bearing surface approximately fitting upon the exterior of the tube l0, and at the diametrically opposite corner I39 bearing upon the side wall of the boiler.

The corner I39 which bears upon the side wall is shown as corrugated, clearly indicated on Figure 6, which indicates how the corrugations may be readily chipped away at one spot to cause the block to fit tightly against the wall, even though projections such as stay-bolts or rivet heads are present at the point of contact.

The corrugations are slightly curved and act as skids to facilitate the sliding of the block upon the side wall.

It will be apparent that to hold these blocks iii effectively in position, the center of gravity of the block must be between a vertical plane through the center of the pipe i and the inner side wall 42 of the boiler, and sufficiently far from the plane through the center of the pipe to cause the block to bear firmly upon the side wall. It is found that the point of contact I39 with the side wall must not be so low as to cause the upper end of the block to wedge itself against the side wall and put the block under compression between the wall and tube, nor to cause the lower end Hi of the block, upon jarring, to move towards the center of the boiler and against the next block, and that the point of contact must not be so high that the lower corner I of the block will move out towards the side wall which would permit the block to drop into the bed of fuel.

In order to keep the block accurately located in place, I find that if a line be drawn from the center of the water tube ill to the point of contact with the side wall of the combustion chamber I39, this line should be not less than 45 degrees nor more than 55 degrees to be horizontal, and that outside of this relatively narrow and critical range displacement of or breakage of the block upon jarring in actual practice takes place in one of the manners above indicated.

Due to the spherical joints between the successive blocks, and the fact that these surfaces are the only contact between the adjacent blocks, the blocks may readily aline themselves, even though the tubes and pipes which support them may not be absolutely straight and even though expansion in successive courses of the blocks may differ as temperatures rise or fall within the boiler.

This again reduces the amount of breakage which is found to occur with other types of joints.

As above mentioned, the tuyeresat the top of the various rows of blocks are made in two sections, the front part 34 being imperforate and the rear part 35 'perforate. The making of the tuyeres in this manner permits the bulk of the air to be ejected laterally, while a substantial quantity of it passes out the rearward side thereof. 1

As will be noted, particularly in Figure 1, these tuyeres extend upwardly into the spaces between other obstructions, such as the water tubes and siphons, and the current of gaseous products of combustion must therefore part and pass about both sides of, as well as over, each tuyre. In doing so, the hot streams of air being ejected laterally through the slots at the sides and tops of the tuyeres, in addition to the eddies caused by the gases passing the tuyeres, cause a very considerable and eifective turbulence, mixing the newly admitted air from the banle wall with the products of combustion, and completing the combustion thereof in the space above the baffle wall and as the gases move into the flue tubes.

The air leaving the tuyeres is heated to a temperature which may at times rise to the vicinity of 1000 degrees F., so that this air, on. mingling with the gaseous products does not cool these and so retard their combustion, but causes immediate combustion of the unburned portion of these products with the oxygen added.

It will be apparent that the amount of air passing through the bafiie wall increases as the suction produced by the draft of the boiler increases, and therefore that the higher be the load at which it is operating, the greater the quantity of air will be supplied, and that this automatically improves the efficiency of the combustion apparatus by maintaining at all times an appropriate supply of oxygen to consume all the combustible constituents of the fuel.

The making the tuyeres in two sections possesses another advantage, in that the front part, being exposed to the radiant heat from the bed of incandescent fuel, becomes substantially hotter than the rear part thereof, and expands therefore at a different rate. This difference in expansion, in a single piece tuyere, is found to cause considerable breakage which is greatly reduced by forming the tuyre in the two halves indicated. Each of these halves is more easily formed, it being smaller, is more easily put into place, while if the front half burns out, it may be replaced without replacement of the rear half. If desired, blocks 3i and also blocks i3i may also be made in two sections and the lower section, being exposed to the radiant heat of the incandescent fuel, will thus be permitted to expand relative the upper section which is shielded from this radiant heat.

The halves of the tuyre not only engage the tapered surface within the last block 32 of the inclined wall, but have substantially horizontal shoulders bearing upon the top of this block which support, positively locates the halves in place.

While I have described the illustrated embodiment of my invention in some particularity, obviously many others will readily occur to those skilled in this art, and I do not, therefore, limit myself to the precise details shown and described, but claim as my invention all embodimerits, variations, and modifications thereof coming within the scope of the appended claims.

I claim:

1. In a combustion apparatus including a combustion chamber, a bafile wall comprising a single layer of blocks having curved engaging surfaces permitting relative angular displacement of successive blocks in any direction while :maintaining substantially constant areas of contact therebetween.

2. In a combustion apparatus including a combustion chamber, a baflle wall comprising :a single layer of blocks each having an opening extending therethrough and curved engaging surfaces surrounding said openings permitting relative angular displacement of successive blocks in any direction.

3. In a combustion apparatus including a combustion chamber, a battle wall comprising a single layer of blocks each having an opening extending therethrough and engaging surfaces of generally spherical-zone shape surrounding said openings permitting relative angular displacement of successive blocks in any direction.

4. In a combustion apparatus including a combustion chamber, a baiiie wall comprising a single layer of blocks each having an opening extending therethrough and engaging surfaces of generally spherical-zone shape surrounding said openings permitting relative angular displacement of successive blocks inany direction, said zones being defined by two planes lying to the same side of a great circle of the surface-defining sphere.

LAWRENCE R. ROBINSON. 

